Apparatus of various character has long been utilized for the purpose of detecting and measuring certain physical phenomenon. For example, in the measurement of mechanical movement, the character of the mechanical movement involved typically dictates the character of the equipment necessary for measurement of the same. In a case of mechanical structures which are subjected to internal pressure, strain gauges may be employed to measure the dimensional changes that are induced by the internal pressure. In the case of mechanical movement of more significant nature, mechanical devices such as micrometers are employed and electrical sensors may also be employed to detect such mechanical movement.
Under certain circumstances it is desirable to measure the flow of fluid such as liquid through a conduit. In the past, this has been accomplished by providing certain types of flow meters such as turbine flow meters, vortex-shedding type flow meters as well as many other flow measurement devices. Most of the flow measurement devices develop either mechanical or electrical interference with the flowing fluid and in many cases such interference is quite undesirable. It is desirable to provide a system for detecting and measuring the flow of fluid through a conduit wherein the flow measurement device or system does not develop mechanical or electrical interference to fluid flow.
In certain cases, it is necessary to measure the extent to which a mechanical object expands and contracts during the various phases of its activity. Many mechanical and electrical devices are provided for the purpose of measuring mechanical expansion and contraction of objects but, for the most part, such devices are complex, are of relatively expensive nature and, in many cases, lack the degree of accuracy that might be desired. Further, it may be desirable that the measuring device or system be such as to permit accurate measuring without the possibility of introducing any mechanical or electrical interference with the object being measured. Few, if any, known measuring devices have this desirable facility.